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The influence of γ-alumina, hydrotalcite, dolomite and Na2CO3 loaded γ-alumina, hydrotalcite, dolomite on fast pyrolysis vapor upgrading of beechwood was investigated using an analytical pyro probe-gas chromatography/mass spectrometry instrument (Py-GC/MS) at a temperature of 500 °C. Overall, this research showcased that these catalysts can deoxygenate biomass pyrolysis vapors into a mixture of intermediate compounds which have substantially lower oxygen content. The intermediate compounds are deemed to be suitable for downstream hydrodeoxygenation processes and it also means that hydrogen consumption will be reduced as a result of moderate in-situ deoxygenation. Among the support catalysts, the application of hydrotalcite yielded the best results with the formation of moderately deoxygenated compounds such as light phenols, mono-oxy ketones, light furans and hydrocarbons with a TIC area % of 7.5, 44.8, 9.8 and 9.8, respectively. In addition, acids were considerably reduced. Dolomite was the next most effective catalyst as γ-alumina retained most of the acids and other oxygenates. Na2CO3 loading on γ-alumina had a noticeable effect on eliminating more or less all the acids, enhancing the mono-oxy-ketones and producing lighter furans. In contrast, Na2CO3 loading on dolomite and hydrotalcite did not show a major impact on the composition except for further enhancing the mono-oxy-ketones (e.g., acetone and cyclopentenones). Additionally, in the case of hydrotalcite and γ-alumina, Na2CO3 loading suppressed the formation of hydrocarbons. In this research, the composition of pyrolytic vapors as a result of catalysis is elaborated further under the specific oxygenate groups such as acids, phenolics, furanics, ketones and acids. Further the catalysts were also characterized by BET, XRD and TGA analysis.
Harsha Mysore Prabhakara; Eddy A. Bramer; Gerrit Brem. Biomass Fast Pyrolysis Vapor Upgrading over γ-Alumina, Hydrotalcite, Dolomite and Effect of Na2CO3 Loading: A Pyro Probe GCMS Study. Energies 2021, 14, 5397 .
AMA StyleHarsha Mysore Prabhakara, Eddy A. Bramer, Gerrit Brem. Biomass Fast Pyrolysis Vapor Upgrading over γ-Alumina, Hydrotalcite, Dolomite and Effect of Na2CO3 Loading: A Pyro Probe GCMS Study. Energies. 2021; 14 (17):5397.
Chicago/Turabian StyleHarsha Mysore Prabhakara; Eddy A. Bramer; Gerrit Brem. 2021. "Biomass Fast Pyrolysis Vapor Upgrading over γ-Alumina, Hydrotalcite, Dolomite and Effect of Na2CO3 Loading: A Pyro Probe GCMS Study." Energies 14, no. 17: 5397.
New regulations aimed at curbing the problem of eutrophication introduce limitations for traditional ways to use the by-product of anaerobic digestion—the digestate. Hydrothermal carbonisation (HTC) can be a viable way to valorise the digestate in an energy-efficient manner and at the same time maximise the synergy in terms of recovery of water, nutrients, followed by more efficient use of the remaining carbon. Additionally, hydrothermal treatment is a feasible way to recirculate recalcitrant process residues. Recirculation to anaerobic digestion enables recovery of a significant part of chemical energy lost in HTC by organics dissolved in the liquid effluent. Recirculating back to the HTC process can enhance nutrient recovery by making process water more acidic. However, such an effect of synergy can be exploited to its full extent only when viable separation techniques are applied to separate organic by-products of HTC and water. The results presented in this study show that using cascade membrane systems (microfiltration (MF) → ultrafiltration (UF) → nanofiltration (NF)), using polymeric membranes, can facilitate such separation. The best results were obtained by conducting sequential treatment of the liquid by-product of HTC in the following membrane sequence: MF 0.2 µm → UF PES 10 → NF NPO30P, which allowed reaching COD removal efficiency of almost 60%.
Agnieszka Urbanowska; Małgorzata Kabsch-Korbutowicz; Christian Aragon-Briceño; Mateusz Wnukowski; Artur Pożarlik; Lukasz Niedzwiecki; Marcin Baranowski; Michał Czerep; Przemysław Seruga; Halina Pawlak-Kruczek; Eduard Bramer; Gerrit Brem. Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance. Energies 2021, 14, 4752 .
AMA StyleAgnieszka Urbanowska, Małgorzata Kabsch-Korbutowicz, Christian Aragon-Briceño, Mateusz Wnukowski, Artur Pożarlik, Lukasz Niedzwiecki, Marcin Baranowski, Michał Czerep, Przemysław Seruga, Halina Pawlak-Kruczek, Eduard Bramer, Gerrit Brem. Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance. Energies. 2021; 14 (16):4752.
Chicago/Turabian StyleAgnieszka Urbanowska; Małgorzata Kabsch-Korbutowicz; Christian Aragon-Briceño; Mateusz Wnukowski; Artur Pożarlik; Lukasz Niedzwiecki; Marcin Baranowski; Michał Czerep; Przemysław Seruga; Halina Pawlak-Kruczek; Eduard Bramer; Gerrit Brem. 2021. "Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance." Energies 14, no. 16: 4752.
Currently, the reclamation and reuse of water have not reached their full potential, although more energy is needed to obtain and transport freshwater and this solution has a more serious environmental impact. Agricultural irrigation is, by far, the largest application of reclaimed water worldwide, so the proposed concept may result in the production of water that can be used, among others, for crop irrigation. This paper describes a novel installation for the recovery of the agricultural water from the digestate, along with the results of initial experiments. Currently, water is wasted, due to evaporation, in anaerobic digestion plants, as the effluent from dewatering of the digestate is discharged into lagoons. Moreover, water that stays within the interstitial space of the digestate is lost in a similar fashion. With increasing scarcity of water in rural areas, such waste should not be neglected. The study indicates that hydrothermal carbonization (HTC) enhances mechanical dewatering of the agricultural digestate and approximately 900 L of water can be recovered from one ton. Dewatered hydrochars had a lower heating value of almost 10 MJ/kg, indicating the possibility of using it as a fuel for the process. The aim of this Design Innovation Paper is to outline the newly developed concept of an installation that could enable recovery of water from, so far, the neglected resource—i.e., digestate from anaerobic digestion plants.
Halina Pawlak-Kruczek; Agnieszka Urbanowska; Weihong Yang; Gerrit Brem; Aneta Magdziarz; Przemyslaw Seruga; Lukasz Niedzwiecki; Artur Pozarlik; Agata Mlonka-Mędrala; Małgorzata Kabsch-Korbutowicz; Eduard A. Bramer; Marcin Baranowski; Małgorzata Sieradzka; Monika Tkaczuk-Serafin. Industrial Process Description for the Recovery of Agricultural Water From Digestate. Journal of Energy Resources Technology 2020, 142, 1 -33.
AMA StyleHalina Pawlak-Kruczek, Agnieszka Urbanowska, Weihong Yang, Gerrit Brem, Aneta Magdziarz, Przemyslaw Seruga, Lukasz Niedzwiecki, Artur Pozarlik, Agata Mlonka-Mędrala, Małgorzata Kabsch-Korbutowicz, Eduard A. Bramer, Marcin Baranowski, Małgorzata Sieradzka, Monika Tkaczuk-Serafin. Industrial Process Description for the Recovery of Agricultural Water From Digestate. Journal of Energy Resources Technology. 2020; 142 (7):1-33.
Chicago/Turabian StyleHalina Pawlak-Kruczek; Agnieszka Urbanowska; Weihong Yang; Gerrit Brem; Aneta Magdziarz; Przemyslaw Seruga; Lukasz Niedzwiecki; Artur Pozarlik; Agata Mlonka-Mędrala; Małgorzata Kabsch-Korbutowicz; Eduard A. Bramer; Marcin Baranowski; Małgorzata Sieradzka; Monika Tkaczuk-Serafin. 2020. "Industrial Process Description for the Recovery of Agricultural Water From Digestate." Journal of Energy Resources Technology 142, no. 7: 1-33.
In this study, conversion times of biomass pyrolysis are measured at temperatures between 450–550°C and particle size fractions between 0–400 μm using a Cyclonic TGA device. Beech, spruce and ash wood are investigated, as well as torrefied samples. The conversion time decreases with increasing temperature from 7 to less than 1 second. The influence of the type of biomass on the conversion time is limited and only significant for low temperatures, when kinetics are dominating the conversion process. A clear influence of the torrefaction process on the pyrolysis conversion time is noted and can be explained by the modified porosity of the biomass particles during the torrefaction process. Kinetic data is extracted from the conversion times, and a model is developed for a better interpretation of the measured results. The model shows good comparison with the experimental data and may also be used for design purposes of fast pyrolysis reactors. This article is protected by copyright. All rights reserved.
Alexander C. Louwes; Ruben B. Halfwerk; Eddy A. Bramer; Gerrit Brem. Experimental Study on Fast Pyrolysis of Raw and Torrefied Woody Biomass. Energy Technology 2019, 8, 1 .
AMA StyleAlexander C. Louwes, Ruben B. Halfwerk, Eddy A. Bramer, Gerrit Brem. Experimental Study on Fast Pyrolysis of Raw and Torrefied Woody Biomass. Energy Technology. 2019; 8 (7):1.
Chicago/Turabian StyleAlexander C. Louwes; Ruben B. Halfwerk; Eddy A. Bramer; Gerrit Brem. 2019. "Experimental Study on Fast Pyrolysis of Raw and Torrefied Woody Biomass." Energy Technology 8, no. 7: 1.
Catalytic tar removal is one of the main challenges restricting the successful commercialization of biomass gasification. Hot gas cleaning using a heterogeneous catalyst is one of the methods used to remove tar. In order to economically remove tar, an efficient low-cost catalyst should be applied. Biomass char has the potential to be such a catalyst. In this work, the reactor parameters that affect the conversion of a model tar component “naphthalene” were investigated employing an in situ thermogravimetric analysis of a fixed bed of biomass char. The following reactor and catalyst parameters were investigated: bed temperature (750 to 900 °C), gas residence time in the char bed (0.4 to 2.4 s), char particle size (500 to 1700 μm), feed naphthalene concentration, feed gas composition (CO, CO2, H2O, H2, CH4, naphthalene, and N2), char properties, and char precursor. It was found that the biomass char has a high activity for naphthalene conversion. However, the catalytic performance of the biomass char was affected by the gasification reactions that consumed its carbon, and the coke deposition that reduced its activity. Furthermore, high ash and iron contents enhanced char activity. The results of this work will be used in the design of a process that uses biomass char as an auto-generated catalyst in the gasification process.
Ziad Abu El-Rub; Eddy Bramer; Samer Al-Gharabli; Gerrit Brem. Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor. Catalysts 2019, 9, 307 .
AMA StyleZiad Abu El-Rub, Eddy Bramer, Samer Al-Gharabli, Gerrit Brem. Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor. Catalysts. 2019; 9 (4):307.
Chicago/Turabian StyleZiad Abu El-Rub; Eddy Bramer; Samer Al-Gharabli; Gerrit Brem. 2019. "Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor." Catalysts 9, no. 4: 307.
Ali Imran; Eddy A. Bramer; K. Seshan; Gerrit Brem. An overview of catalysts in biomass pyrolysis for production of biofuels. Biofuel Research Journal 2018, 5, 872 -885.
AMA StyleAli Imran, Eddy A. Bramer, K. Seshan, Gerrit Brem. An overview of catalysts in biomass pyrolysis for production of biofuels. Biofuel Research Journal. 2018; 5 (4):872-885.
Chicago/Turabian StyleAli Imran; Eddy A. Bramer; K. Seshan; Gerrit Brem. 2018. "An overview of catalysts in biomass pyrolysis for production of biofuels." Biofuel Research Journal 5, no. 4: 872-885.
CO2 capture from ambient air is an interesting option for CO2 enrichment in greenhouses. In this study, adsorbents comprised of hydrated Na2CO3 supported over activated carbon honeycombs were prepared, characterized and tested for CO2 capture from air. The adsorption of H2O and the formation of the hydrates were studied by means of FT-IR spectroscopy. The inlet CO2 concentration showed to have a major influence on the conversion yield into NaHCO3, and the results fitted well to the Toth model. A statistical model of the CO2 capture capacity was obtained to get insight into the key parameters of the adsorption process. The air temperature and its moisture content showed to have the largest impact on the CO2 capture, while the flow rate had a minor influence. The chemical reaction path during the CO2 adsorption showed to be determined by the relative humidity conditions inside the reactor. Addition of more salt on the carrier showed to improve the CO2 capture capacity, but this is limited by the strength of the honeycomb carrier. Finally, a preliminary desorption test via a mild temperature and moisture swing was run to assess the feasibility of the process for application in greenhouses. The results showed that the required volume of adsorbent would be roughly 1/1000 of the total volume of a closed greenhouse assuming a target CO2 level of 1200 ppm.
Rafael Rodríguez-Mosqueda; Eddy A. Bramer; Gerrit Brem. CO2 capture from ambient air using hydrated Na2CO3 supported on activated carbon honeycombs with application to CO2 enrichment in greenhouses. Chemical Engineering Science 2018, 189, 114 -122.
AMA StyleRafael Rodríguez-Mosqueda, Eddy A. Bramer, Gerrit Brem. CO2 capture from ambient air using hydrated Na2CO3 supported on activated carbon honeycombs with application to CO2 enrichment in greenhouses. Chemical Engineering Science. 2018; 189 ():114-122.
Chicago/Turabian StyleRafael Rodríguez-Mosqueda; Eddy A. Bramer; Gerrit Brem. 2018. "CO2 capture from ambient air using hydrated Na2CO3 supported on activated carbon honeycombs with application to CO2 enrichment in greenhouses." Chemical Engineering Science 189, no. : 114-122.
Supercritical Water Gasification is an efficient technology in converting wet biomass into H2 and CH4 in comparison to other conventional thermochemical processes. Coke deposition, however, remains as a major challenge in this technology. Coke formation is the result of polymerization reactions that take place at sub-critical conditions. Directly injecting the relatively unheated wet biomass feed into supercritical water increases the heating rate and reduces the residence time of the feed in the sub-critical condition. This leads to a minimized coke formation in the process. However, a non-isothermal mixing takes place during this direct injection that is less energy-efficient. In addition, the biomass feedstream experiences less pre-heating that means less heat recovery from the product gas. These two aspects might reduce the overall process performance. Parametric studies of key operating parameters, such as operating temperature, dry matter content, bypass water ratio and heat exchanger effectiveness, are carried out to investigate the influence of direct injection to the thermal efficiency of the system. Subsequently, optimization using pinch analysis is conducted to the system with direct injection. Finally, an operating window for optimum performance of the optimized direct injection gasification system is proposed.
Riza Yukananto; Alexander C. Louwes; Eddy A. Bramer; Gerrit Brem. An Energy Analysis on Gasification of Sewage Sludge by a Direct Injection in Supercritical Water. American Journal of Analytical Chemistry 2017, 08, 753 -773.
AMA StyleRiza Yukananto, Alexander C. Louwes, Eddy A. Bramer, Gerrit Brem. An Energy Analysis on Gasification of Sewage Sludge by a Direct Injection in Supercritical Water. American Journal of Analytical Chemistry. 2017; 08 (12):753-773.
Chicago/Turabian StyleRiza Yukananto; Alexander C. Louwes; Eddy A. Bramer; Gerrit Brem. 2017. "An Energy Analysis on Gasification of Sewage Sludge by a Direct Injection in Supercritical Water." American Journal of Analytical Chemistry 08, no. 12: 753-773.
Bio-oil produced from conventional flash pyrolysis has poor quality and requires expensive upgrading before it can be used as a transportation fuel. In this work, a high quality bio-oil has been produced using a novel approach where flash pyrolysis, catalysis and fractionation of pyrolysis vapors using two stage condensation are combined in a single process unit. A bench scale unit of 1 kg/h feedstock capacity is used for catalytic pyrolysis in an entrained down-flow reactor system equipped with two-staged condensation of the pyrolysis vapor. Zeolite-based catalysts are investigated to study the effect of varying acidities of faujasite Y zeolites, zeolite structures (ZSM5), different catalyst to biomass ratios and different catalytic pyrolysis temperatures. Low catalyst/biomass ratios did not show any significant improvements in the bio-oil quality, while high catalyst/biomass ratios showed an effective deoxygenation of the bio-oil. The application of zeolites decreased the organic liquid yield due to the increased production of non-condensables, primarily hydrocarbons. The catalytically produced bio-oil was less viscous and zeolites were effective at cracking heavy molecular weight compounds in the bio-oil. Acidic zeolites, H-Y and H-ZSM5, increased the desirable chemical compounds in the bio-oil such as phenols, furans and hydrocarbon, and reduced the undesired compounds such as acids. On the other hand reducing the acidity of zeolites reduced some of the undesired compounds in the bio-oil such as ketones and aldehydes. The performance of H-Y was superior to that of the rest of zeolites studied: bio-oil of high chemical and calorific value was produced with a high organic liquid yield and low oxygen content. H-ZSM5 was a close competitor to H-Y in performance but with a lower yield of bio-oil. Online fractionation of catalytic pyrolysis vapors was employed by controlling the condenser temperature and proved to be a successful process parameter to tailor the desired bio-oil properties. A high calorific value bio-oil having up to 90% organics was produced using two staged condensation of catalytic pyrolysis vapor. Zeolite-based acidic catalysts can be used for selective deoxygenation, and the catalytic bio-oil quality can be further improved with staged vapor condensation.
Ali Imran; Eddy A. Bramer; Kulathuiyer Seshan; Gerrit Brem. Catalytic Flash Pyrolysis of Biomass Using Different Types of Zeolite and Online Vapor Fractionation. Energies 2016, 9, 187 .
AMA StyleAli Imran, Eddy A. Bramer, Kulathuiyer Seshan, Gerrit Brem. Catalytic Flash Pyrolysis of Biomass Using Different Types of Zeolite and Online Vapor Fractionation. Energies. 2016; 9 (3):187.
Chicago/Turabian StyleAli Imran; Eddy A. Bramer; Kulathuiyer Seshan; Gerrit Brem. 2016. "Catalytic Flash Pyrolysis of Biomass Using Different Types of Zeolite and Online Vapor Fractionation." Energies 9, no. 3: 187.
Ali Imran; Eddy A. Bramer; Kulathuiyer Seshan; Gerrit Brem. Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts. Journal of Analytical and Applied Pyrolysis 2016, 117, 236 -246.
AMA StyleAli Imran, Eddy A. Bramer, Kulathuiyer Seshan, Gerrit Brem. Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts. Journal of Analytical and Applied Pyrolysis. 2016; 117 ():236-246.
Chicago/Turabian StyleAli Imran; Eddy A. Bramer; Kulathuiyer Seshan; Gerrit Brem. 2016. "Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts." Journal of Analytical and Applied Pyrolysis 117, no. : 236-246.
Torrefaction is a thermochemical pre-treatment process for upgrading the properties of biomass to resemble those of fossil fuels such as coal. Biomass properties of particular interest are chemical composition, physical property and combustion characteristics. In this work, torrefaction of beech wood and miscanthus (sinensis) was carried out to study the influence of torrefaction temperature (240–300 °C) and residence time (15–150 min) on the aforementioned properties of the biomass. Results of the study revealed that torrefaction temperature has a significant influence on mass and energy yields, whereas the influence of the residence time becomes more apparent for the higher torrefaction temperatures (>280 °C). Torrefied miscanthus resulted in higher energy densification compared to beech wood for a residence time of 30 min. A significant improvement in grindability of the torrefied beech wood was obtained even for lightly torrefied beech wood (at 280 °C and 15 min of residence time). Observation from the combustion study showed that the ignition temperature is slightly affected by the torrefaction temperature. As a whole, the torrefaction temperature determines the characteristics of the torrefied fuel compared to other process parameters like residence time. Furthermore, with optimal process conditions, torrefaction produces a solid fuel with combustion reactivity and porosity comparable to raw biomass, whereas grindability and heating value are comparable to low quality coal.
Eyerusalem M. Gucho; Khurram Shahzad; Eddy A. Bramer; Niaz A. Akhtar; Gerrit Brem. Experimental Study on Dry Torrefaction of Beech Wood and Miscanthus. Energies 2015, 8, 3903 -3923.
AMA StyleEyerusalem M. Gucho, Khurram Shahzad, Eddy A. Bramer, Niaz A. Akhtar, Gerrit Brem. Experimental Study on Dry Torrefaction of Beech Wood and Miscanthus. Energies. 2015; 8 (5):3903-3923.
Chicago/Turabian StyleEyerusalem M. Gucho; Khurram Shahzad; Eddy A. Bramer; Niaz A. Akhtar; Gerrit Brem. 2015. "Experimental Study on Dry Torrefaction of Beech Wood and Miscanthus." Energies 8, no. 5: 3903-3923.
Performance of a novel alumina-supported sodium carbonate catalyst was studied to produce a valuable bio-oil from catalytic flash pyrolysis of lignocellulosic biomass. Post treatment of biomass pyrolysis vapor was investigated in a catalyst fixed bed reactor at the downstream of the pyrolysis reactor. In-situ catalytic upgrading of biomass pyrolysis vapor was conducted in an entrained flow pyrolysis reactor by feeding a premixed feedstock of the catalyst and biomass. Na2CO3/gamma-Al2O3 was very effective for de-oxygenation of the pyrolysis liquid and oxygen content of the bio-oil was decreased from 47.5 wt.% to 16.4 wt.%. An organic rich bio-oil was obtained with 5.8 wt.% water content and a higher heating value of 36.1 MJ/kg. Carboxylic acids were completely removed and the bio-oil had almost a neutral pH. This bio-oil of high calorific low, low water and oxygen content may be an attractive fuel precursor. In-situ catalytic upgrading of biomass pyrolysis vapor produced a very similar quality bio-oil compared to post treatment of pyrolysis vapors, and shows the possible application of Na2CO3/gamma-Al2O3 in a commercial type reactor system such as a fluidized bed reactor. (C) 2014 Elsevier B.V. All rights reserved
Ali Imran; Eddy A. Bramer; Kulathuiyer Seshan; Gerrit Brem. High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate. Fuel Processing Technology 2014, 127, 72 -79.
AMA StyleAli Imran, Eddy A. Bramer, Kulathuiyer Seshan, Gerrit Brem. High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate. Fuel Processing Technology. 2014; 127 ():72-79.
Chicago/Turabian StyleAli Imran; Eddy A. Bramer; Kulathuiyer Seshan; Gerrit Brem. 2014. "High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate." Fuel Processing Technology 127, no. : 72-79.
Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of the primary air speed, fuel moisture and inert content on the combustion characteristics (ignition rate, combustion rate, ignition front speed and temperature of the reaction zone) is evaluated. The upward combustion concept decouples the drying, devolatilization and burnout phase. In this way the moisture and inert content of the waste have almost no influence on the combustion process. In this paper an experimental comparison between conventional and reversed combustion is presente
Miladin Markovic; Eddy A. Bramer; Gerrit Brem. Experimental investigation of wood combustion in a fixed bed with hot air. Waste Management 2014, 34, 49 -62.
AMA StyleMiladin Markovic, Eddy A. Bramer, Gerrit Brem. Experimental investigation of wood combustion in a fixed bed with hot air. Waste Management. 2014; 34 (1):49-62.
Chicago/Turabian StyleMiladin Markovic; Eddy A. Bramer; Gerrit Brem. 2014. "Experimental investigation of wood combustion in a fixed bed with hot air." Waste Management 34, no. 1: 49-62.
Heat transfer to water at supercritical pressures has been numerically investigated using a two-dimensional modeling approach. The simulations in a two-dimensional domain have been performed using the low-Reynolds k–ϵ turbulence model, and the IAPWS-IF97 formulation to describe the properties of water at different conditions. The accuracy of the model is validated using an experimental setup at supercritical pressures. The experimental dataset was obtained in supercritical water flowing upward in a 0.4 m long vertical bare tube with 10 mm ID. The temperature data were collected at multiple heights in the tube and at pressures of about 24 MPa, an inlet temperature of 300 °C, values of mass flux ranged from 6.6 to 10 kg/m2 s and an outer wall temperature of 300 °C resulting in bulk-fluid temperatures exceeding the pseudo-critical temperature. The comparison of the temperature results shows a good agreement for low mass fluxes between the experimental and numerical data. At these low flow conditions, the 2D model predicts recirculation zones near the inlet which results in a more complex simulation. The accuracy of the 2D model for higher fluxes cannot be properly assessed on basis of the experimental data because of practical limitation of the setup. But the accuracy of the 2D model for the higher mass flow cases is expected to be even more accurate, due to less complexity in the flow calculation because of smaller buoyancy effects. Finally simulation results of the two-dimensional model at higher mass flows are compared with several frequently used one-dimensional correlations from literature for heat transfer at supercritical pressures.
Jan A.M. Withag; Joost L.H.P. Sallevelt; Derk W.F. Brilman; Eddy A. Bramer; Gerrit Brem. Heat transfer characteristics of supercritical water in a tube: Application for 2D and an experimental validation. The Journal of Supercritical Fluids 2012, 70, 156 -170.
AMA StyleJan A.M. Withag, Joost L.H.P. Sallevelt, Derk W.F. Brilman, Eddy A. Bramer, Gerrit Brem. Heat transfer characteristics of supercritical water in a tube: Application for 2D and an experimental validation. The Journal of Supercritical Fluids. 2012; 70 ():156-170.
Chicago/Turabian StyleJan A.M. Withag; Joost L.H.P. Sallevelt; Derk W.F. Brilman; Eddy A. Bramer; Gerrit Brem. 2012. "Heat transfer characteristics of supercritical water in a tube: Application for 2D and an experimental validation." The Journal of Supercritical Fluids 70, no. : 156-170.
To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The incoming radiative heat flux, sample thickness and moisture content are some of the used variables. Not only the ignition time can be calculated with the model, but also the mass flux and surface temperature at ignition. The ignition times for softwoods and PMMA are mainly under-predicted. For hardwoods and PVC the predicted ignition times agree well with experimental results. Due to a significant scatter in the experimental data the mass flux and surface temperature calculated with the model are hard to validate. The model is applied on the startup of a municipal waste incineration plant. For this process a maximum allowable primary air flow is derived. When the primary air flow is above this maximum air flow, no ignition can be obtaine
Maarten van Blijderveen; Eddy A. Bramer; Gerrit Brem. Modelling piloted ignition of wood and plastics. Waste Management 2012, 32, 1659 -1668.
AMA StyleMaarten van Blijderveen, Eddy A. Bramer, Gerrit Brem. Modelling piloted ignition of wood and plastics. Waste Management. 2012; 32 (9):1659-1668.
Chicago/Turabian StyleMaarten van Blijderveen; Eddy A. Bramer; Gerrit Brem. 2012. "Modelling piloted ignition of wood and plastics." Waste Management 32, no. 9: 1659-1668.
Heat transfer in water at supercritical pressures has been investigated numerically using a one-dimensional modeling approach. A 1D plug flow model has been developed in order to make fast predictions of the bulk-fluid temperature in a tubular flow. The chosen geometry is a vertical tube with an inner diameter of 10 mm and a heated length of 4.0 m. The simulations concern a heated upward flow with an imposed wall temperature profile. Viscous effects, internal conduction and enthalpy changes due to a pressure gradient have been neglected after evaluation of the governing equations in dimensionless form. The resulting set of equations is closed using Nusselt correlations found in literature and solved using an explicit Euler scheme to simulate heat transfer in a supercritical water flow. The results for three different cases show that the model is able to accurately predict the bulk temperature based on heat transfer rates provided by a suitable Nusselt correlation. However, there is also reason to assume that these correlations are very specific for the flow conditions, since boiling effects occurring at certain conditions can highly influence the heat transfer rate. As a consequence, the model may be unable to describe supercritical heat transfer over a broad range of configurations when only using one correlation. The agreement of these results with the two-dimensional simulations will be investigated in a separate article. The description of the model is preceded by a mathematical description of supercritical water flows and by an overview of the supercritical heat transfer phenomena as observed in earlier studies.
Joost L.H.P. Sallevelt; Jan A.M. Withag; Eddy A. Bramer; Derk W.F. Brilman; Gerrit Brem. One-dimensional model for heat transfer to a supercritical water flow in a tube. The Journal of Supercritical Fluids 2012, 68, 1 -12.
AMA StyleJoost L.H.P. Sallevelt, Jan A.M. Withag, Eddy A. Bramer, Derk W.F. Brilman, Gerrit Brem. One-dimensional model for heat transfer to a supercritical water flow in a tube. The Journal of Supercritical Fluids. 2012; 68 ():1-12.
Chicago/Turabian StyleJoost L.H.P. Sallevelt; Jan A.M. Withag; Eddy A. Bramer; Derk W.F. Brilman; Gerrit Brem. 2012. "One-dimensional model for heat transfer to a supercritical water flow in a tube." The Journal of Supercritical Fluids 68, no. : 1-12.
Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140 °C. In previous experiments it is found that at temperatures around 200 °C, in some circumstances, self- or spontaneous ignition can be achieved. Using preheated air can be a powerful tool to control the ignition and combustion processes in a waste combustion plant. To use this tool effectively, the influence of the preheated air on the fuel bed needs to be well understood. The present work is done to investigate in a systematically way the spontaneous ignition behaviour of a packed bed heated with a preheated air stream. Experiments on a lab scale packed bed reactor are carried out for various fuel types. Because MSW is an highly inhomogeneous fuel, wood and char are used as model fuels. To include the inhomogeneous character of MWS, also experiments are carried out with RDF. Parameters such as primary air flow velocity and temperature, addition of inert material, moisture content of the fuel (wood chips) and particle size (char) have been changed to see their effect on the spontaneous ignition temperature and on the minimum air temperature needed for ignition. The spontaneous ignition temperature is defined as the bed temperature at which a transition takes place from a negligible or slow fuel reaction rate to a rapid oxidation of either the volatiles or the solid fuel without an external source such as a spark or a flame. The minimum or critical air temperature is defined as the lowest air temperature at which ignition can be obtained. It is found that the type of fuel has influence on the ignition temperatures. Besides both the critical air temperature needed for the spontaneous ignition and the spontaneous ignition temperature increase with an increase in the primary air velocity (between 0.1 and 0.5 m/s) and increasing the added inert fraction (between 0 and 40 wt%), irrespective of the fuel type. The effect of air flow velocity and temperature and also the effect of inert on both the critical air temperature and the spontaneous ignition temperature can be explained qualitatively by using Semenov’s analysis of thermal explosions. Semenov’s theory is quantitatively applied to predict the spontaneous ignition and the critical air temperatures for wood.
Maarten Van Blijderveen; Eyerusalem M. Gucho; Eddy A. Bramer; Gerrit Brem. Spontaneous ignition of wood, char and RDF in a lab scale packed bed. Fuel 2010, 89, 2393 -2404.
AMA StyleMaarten Van Blijderveen, Eyerusalem M. Gucho, Eddy A. Bramer, Gerrit Brem. Spontaneous ignition of wood, char and RDF in a lab scale packed bed. Fuel. 2010; 89 (9):2393-2404.
Chicago/Turabian StyleMaarten Van Blijderveen; Eyerusalem M. Gucho; Eddy A. Bramer; Gerrit Brem. 2010. "Spontaneous ignition of wood, char and RDF in a lab scale packed bed." Fuel 89, no. 9: 2393-2404.